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Redo file containes records called redo entires. Each record will be represent before/after image of data(irrespective of whether committed or uncommitted)or you can say any entry in the rollback segment will generate redo.

dear sir
following Text is from Oracle documentation
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Online Redo Log Contents
Online redo log files are filled with redo records. A redo record, also called a redo entry, is made up of a group of change vectors, each of which is a description of a change made to a single block in the database. For example, if you change a salary value in an employee table, you generate a redo record containing change vectors that describe changes to the data segment block for the table, the rollback segment data block, and the transaction table of the rollback segments.

Redo entries record data that you can use to reconstruct all changes made to the database, including the rollback segments. Therefore, the online redo log also protects rollback data. When you recover the database using redo data, Oracle reads the change vectors in the redo records and applies the changes to the relevant blocks.

Redo records are buffered in a circular fashion in the redo log buffer of the SGA and are written to one of the online redo log files by the Oracle background process Log Writer (LGWR). Whenever a transaction is committed, LGWR writes the transaction's redo records from the redo log buffer of the SGA to an online redo log file, and a system change number (SCN) is assigned to identify the redo records for each committed transaction. Only once all redo records associated with a given transaction are safely on disk in the online logs is the user process notified that the transaction has been committed.

Redo records can also be written to an online redo log file before the corresponding transaction is committed. If the redo log buffer fills, or another transaction commits, LGWR flushes all of the redo log entries in the redo log buffer to an online redo log file, even though some redo records may not be committed. If necessary, Oracle can roll back these changes.
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Re: content of the redo log file

I wanted to know, what is the content of redo log file? Does it store all the commited or uncommited statement executed by a user or something else?

Please, I need your suggestions

Thanks in Advance
Shailendra

Yes it stores all commited and uncomitted changes.
You can say all changes that are being made to a database are first recorded in the redolog files. (ofcource there are exceptions like no logging etc). But the basic funda is that no changes can be recorded in database unless it is first written to redo logs.
And redo log are used only and only for recovery and nothing else.

Amar"There is a difference between knowing the path and walking the path."

Re: Re: content of the redo log file

Originally posted by adewri Yes it stores all commited and uncomitted changes.
You can say all changes that are being made to a database are first recorded in the redolog files. (ofcource there are exceptions like no logging etc). But the basic funda is that no changes can be recorded in database unless it is first written to redo logs.
And redo log are used only and only for recovery and nothing else.

Just to add the logfiles nature: in the event of recovering stages it might be useful in ROLLFORWARD Mechanism.

Re: Re: Re: content of the redo log file

Originally posted by vastdba Just to add the logfiles nature: in the event of recovering stages it might be useful in ROLLFORWARD Mechanism.
VAST

Gee, here he goes again, showing off with his "vast" knowledge of Oracle RDBMS!

VAST, it realy isn't necessary to respond to each and every post unless you realy have to say something that is related to the subject! Your confusing and incorrect/inacurate answers only adds to the confusion of the original posters!

Jurij ModicASCII a stupid question, get a stupid ANSI
24 hours in a day .... 24 beer in a case .... coincidence?